Creating Magnetically Inducible Synthetic Gene Networks for Cell and Tissue Therapies Project Summary Despite significant investment, cardiovascular disease is the leading cause of death in the United States. Efforts to engineer replacements for diseased cardiovascular tissues hold significant therapeutic potential. The ultimate goal of these tissue engineering studies is to generate functional tissue that can completely replace damaged tissue by replicating the native tissue's endogenous chemical, electrical, and mechanical properties. In the laboratory, several tissue types have been created, yet only a few of these (e.g, skin, bone) have successfully translated to clinical application. One of the significant challenges in engineering cardiovascular tissues is recreating the spatially varying cellular heterogeneity of native tissue in vitro prior to implant. After implant, directing cellular phenotype within the engineered tissue is an even greater challenge. There is an urgent need to create a robust approach that can safely direct cellular phenotypes within an engineered tissue both pre- and particularly post-implant, because once we have it, clinicians will be able to customize tissue implants in situ to ensure that spatially varying cellular phenotypes are matched to an individual patient's implant site. To this end, my group's long-term goal is to use magnetic fields to reprogram engineered cardiovascular tissues implanted in the body. Our overall objective here, which is the next step in pursuit of this goal, is to create a magnetically inducible synthetic gene network (in human cells. Our central design premise is that we can create a protein scaffold that responds to magnetic force by sequestering an engineered transcription factor, thus turning off engineered gene transcription when a magnetic field is applied. We expect to create a transformative tool for modulating cell phenotype using electromagnetic energy, complementary to the field of optogenetics, that will advance a broad range of biomedical studies where new cellular inputs are required to test hypotheses. Equally important, this result will have positive impact in new potential therapies, particularly in cardiovascular disease. Because magnetic fields can penetrate tissue in cases where light or pharmaceuticals may not, this tool will have the potential to transform cardiovascular therapies as well as a range of therapies based on engineered cells. 1